Molded plastic stick for a swab



July 15, 1958 C. CASTELLI MOLDED PLASTIC STICK FOR A SWAB Filed June 1. 1954 INVENTOR (W424 6 C'AJIZ'LLI MQLDED PLASTIC $TICK FOR A SWAB Charles 'Casteili, New Brunswick, N. J., assignor to Johnson & .lohnsomn corporation of New Jersey Application June 1,1954, Serial No. 433,398

Claims. (Cl. 15- 143) The present invention relates to. a, barbed, plastic stick for a swab having cotton or other fibrouslmateiial secured at one, and preferably. both, ends of the stick.

The ordinary cotton swab is formed of a roundwooden stick having a cotton tip secured atone or both ends. The product is adapted to be used:in;cleansing or lubricating body cavities of the-infant,rapplying COS") metics, etc. Adhesive of one sortonanotherzisgenerally used to secure the fibers to the end of. the stick.

Cotton swabs which have employed the wooden stick have had certain inherent disadvantageous qualities. For instance, it would be desirable, if possible, to avoid the necessity of employing an adhesiveto secure the fibers to the sticksince incorporating adhesive in the product by using the automatic machines for manufacture of this type of product has .involvedmany complenities in the operation. Further, wood does not have desired high aesthetic appeal.

One advantage of the present invention is .that in achieving the objects thereof a productjias .been obtained in which no adhesive securing .thefibers tothe stick end need be used, and the productfurther. has high aesthetic properties not. enjoyed by the conventional wooden stick.

The invention and its several features may be conveniently understood by considering the appended drawings in connection with the following description.

Fig. 1 is an isometric View of a cotton swab.

Fig. 2 is a side view of the product of Figl drawn to a larger scale.

Fig. 3 is a side viewof the end ofsthe supporting stick before applying the cotton or other fibers to formwthe tip.

Fig. 4 is an end view of the stick shown in Fig. 3.

Fig. 5 is a view similar to Fig. 3 showing a stick according to another embodiment of the invention with the outline of the fibrous tip shown by dotted lines.

Fig. 6 is an end view of the product of Fig. 5 drawn to a larger scale.

Fig. 7 is a side view of the end of a stick according n to still another embodiment of the invention before applying the fibrous tip.

Fig. 8 is a view similar to Fig. 7 showing still another embodiment of the invention.

Fig. 9 is an end view of the stick shown in Fig. 8.

Referring for the moment to Figs. 1 to 4, inclusive, reference number 10 designates in general the supporting stick for the cotton swab according to the invention. The stick is formed of a central portion 11 having a relatively large diameter, and end portions 12 having relatively smaller or reduced diameter, and separated from the central portion 11 by tapered portions 15. The tip which is formed of fibers of cotton or other suitable fibrous material, preferably cellulosic material such as rayon, is shown at 16. Stick 10 is made of suitable plastic material such as polystyrene, polyvinyl chloride or polyvinyl chloride-polyvinyl acetate copoly- 2,842,790 Patented July 15, 1958 mer, having the necessary rigidity. Cotton tip 16 is secured to-endportion 12 by means of barbs 17.

Stick 10 is formed by molding, preferably injection molding technique which is well known in the art. Split molds of suitable shape to form opposite halves of stick 10 are provided, the parting plane of the molds being designated with reference to the molded stick by line A of Figs. 4, 6, 8 and 9. Barbs or lugs 17, as seen in Figs.

.3 and 4, have outward and inward dimension, i. e. transverse surfaces 20 and21, respectively, and opposite sidewise dimension, i. e. longitudinal surfaces 22and 25. It will be noted that the'Figs. 3 and 4 embodiment of the invention is provided with two rows of barbs oppositely spacedon the stick end, the barbs, in each row being staggered in relation to the barbs in the other row. A further characteristic of this preferred embodiment is that the barbs or lugs 17 occupy a very small proportion of the total surfaceof end section 12, the

importance of which will be explained more fully hereinafter.

Another feature of the Figs. 3 and 4 embodiment, which is particularly preferred for invention purposes, lies in the relative position of plane A to plane B, the latter being the plane which includes longitudinal surface 25 of barbs 17. That is, the mold is so formed, and the plastic stick thereby so molded, that angle A-B is at least 10.

During manufacture of the cotton swab, the stick 10 is rotated, usually automatically, in proximity to a small mass of cotton just equal to the amount of cotton desired in the finished tip. By providing the angle AB as just described, optimum conditions are maintained to cause the barbs 17 to pick up fibers of cotton from the mass and thereby wind the cotton to the desired degree of firmness adequately secured to the end of stick without employing adhesive.

Another preferred feature of the invention lies in the relativeposition of plane C, normal to the axis of stick 10, and plane D which includes the inward transverse side of the barb 17. Angle CD is preferably at least about. 10 in order to provide an inward corner-27 which will-firmly secured cotton tip 16 to end 12 without emplaying adhesive.

Suitable specificdimensions for the structure shown in Figs. 1 to-4, inclusive, are a 0.10 inch diameterpof central portion of stick 10, 0.060 inch diameter for re- .ducedend section 12, 0.050 inch between barbs.17 in a given row, and 0.035 inch overall longitudinal dimension for each barb 17. Angle CD may be 20, and angle AB may be 20. The transverse dimension of each barb 17 may be 0.035 inch and the height of each barb 0.02 inch. The minimum height of each barb 1'7 necessary to be effective in accumulating and holding the fibers is about & inch.

Turning now to Figs. 5 and 6, it will be seen that four rows, rather than two rows, of barbs are provided. Two of the rows of barbs 17 may be of form similar to barbs 17 of Fig. 3, and the other two oppositely-spaced rows of barbs 30 of somewhat difierent construction. In view of the location of parting plane A with reference to barbs 30, transverse surfaces 31 and longitudinal surfaces 32 are formed relatively perpendicular to plane A with only enough angle to provide mold clearance. Although lugs or barbs 17 in opposite rows are placed symmetrically, it will be noted that barbs in adjacent rows are staggered in relation to each other. That is, barbs 17 are staggered with relation to the barbs 30, and vice verse. This is an advantageous feature of the invention in providing optimum pick-up of fibers by the barbs.

Fig. 7 illustrates a structure within the broader scope of the invention in that both the transverse and the longitudinal surfaces of lugs 30 are parallel either to parting plane A, or the longitudinalplane perpendicular thereto. It will be noted that the Fig. 7 embodiment incorporates the feature of staggered barbs in adjacent rows, however.

The stick shown in Figs. 8 and 9 has barbs or lugs 35 of diamond-shaped construction. Two rows of barbs 36 are disposed on opposite sides of end 12 and on parting plane A, and intermediate these two rows there are provided opposite rows of barbs 35. Barbs 36 have inward edges 40 and sidewise edges 41. Plane F is a longitudinal plane including sidewise edge 41, and plane E is a transverse plane including inward edge 40. For reasons similar to those discussed above in connection with angle AB, angle AF is preferably at least 10, and for reasons similar to those discussed above in connection with angle CD, angle C--E is also preferably at least 10. Likewise, the surfaces and edges of lugs 35, for the same reasons as discussed in connection with barbs 30 of Fig. 5, are about perpendicular to plane A with only enough angle to provide for mold clearance.

In all of the embodiments described above a significant feature is that most of stick end 12, defined by the area which is to be in contact with fibers, is free of barbs. In the Figs. 1 to 4 embodiment, which has certain advantages from the standpoint of capability of the end 12 to pick up the fibers, the barbed area of end 12 is not more than about 10%. As a preferred maximum, represented by the stick end illustrated and described in connection with Figs. 5 to 9, inclusive, the barbed area of stick end 12 should not be more than 20%.

When utilizing the diamond-shaped barbs of the type illustrated in Fig. 8, a particular embodiment, not illustrated specifically, employs two, rather than four, oppositely-placed rows of barbs in staggered relation on parting plane A, the over-all structure being similar to that shown in Fig. 3, except that the barbs are diamond-shaped rather than square.

In co-pending application Ser. No. 258,782 there are described and claimed cotton swabs which are secured to the end of a stick and are bonded to retain and restrain loose surface fibers by application of methyl cellulose, ethyl cellulose, polyvinyl alcohol, or other suitable bonding agent. One preferred embodiment of the invention described in the present application is the incorporation of the structural features hereof, i. e. use of a plastic molded stick having retaining barbs or lugs, a tip of cellulosic fibrous material and also the bonding agent disclosed and claimed in Ser. No. 258,782. The features of the copending application cooperate with the present application by retaining the fibers within a zone where they may be eifectively held without adhesive, thereby to produce a cotton swab having a desirably compact, wellretained cotton tip free from loose unrestrained surface fibers.

Although certain specific and preferred embodiments of the invention have been described hereinabove, it is understood that these descriptions are presented not in a limiting sense. For example, the barbs, instead of being square or diamond-shaped, may be triangular or other suitable shape if desired. Although a particular embodiment is directed to rows of barbs on the stick end, this again is not limiting, for the barbs may be randomly placed. The measure of protection sought is defined by the appended claims, affording to the claims the benefit of all modifications and equivalents apparent to those skilled in the art.

I claim:

1. A molded plastic stick comprising a barbed end portion adapted to secure a fibrous swab, the longitudinally sidewise edge faces of the barbs inclining radially inwardly toward the longitudinal axis of said stick, the barbed area of said fiber-retaining end being not greater than 20% of the total area of said end.

2. A molded plastic stick of claim 1 wherein the longitudinally inward edge faces of the barbs are inclined to the radius and toward the near, axial end of the stick.

3. A molded plastic stick of claim 2 having two oppm site rows of barbs.

4. A molded plastic stick of claim 3 being free of barbs between the opposite rows of barbs, the barbs in said rows being staggered with relation to each other, the sidewise edge faces of the barbs inclining radially inwardly toward said plane at an angle of at least about 10, the inward edge faces of said barbs being inclined to the radius toward the near, axial end of the stick at an angle of at least about 10, the barbed area of said fiber-retaining end being not greater than 10% of the total area of said end.

5. A molded plastic stick of claim 4 having not more than two intervening rows of barbs, the barbs being substanitally square and having longitudinal surfaces substantially parallel with the axis of said stick.

References Cited in the file of this patent UNITED STATES PATENTS 1,962,875 Reber June 12, 1934 2,068,162 Borchers Ian. 19, 1937 2,242,543 Phipps May 20, 1941 2,618,027 Barber Nov. 18, 1952 2,705,009 Plantinga Mar. 29, 1955 

